Reduce Milestoneish::DISPLAY_ISSUES_LIMIT to 500

app/models/concerns/milestoneish.rb

 # frozen_string_literal: true
 
 module Milestoneish
-  DISPLAY_ISSUES_LIMIT = 3000
+  DISPLAY_ISSUES_LIMIT = 500
 
   def total_issues_count
     @total_issues_count ||= Milestones::IssuesCountService.new(self).count

changelogs/unreleased/jl-lower-milestone-issue-display-limit.yml

+---
+title: Reduce milestone issue list display limit to 500
+merge_request: 58168
+author:
+type: performance